Pearson is known primarily for two published works, the first being his essay, Fretful Sleepers: A Sketch of New Zealand Behaviour and Its Implications for the Artist, originally appearing in Landfall in 1952, and the second being his only novel, Coal Flat, which, at more than 400 pages, was the longest New Zealand novel when first published in 1963.

As Peter Simpson notes in his review of Millar's biography of Pearson, "Fretful Sleepers is a trenchant study of the drive to conformity in New Zealand", while Coal Flat embedded "within it the social analysis informing Fretful Sleepers, but focusing on characters and events in a small West Coast coal mining town (based on Blackball where Pearson had briefly taught school and worked in a mine)".

Due to Pearson's closeted homosexuality and his fear of being exposed in the intolerant years before 1986's Homosexual Law Reform Bill, his career as a novelist began and ended with the largely autobiographical Coal Flat, where he had originally intended the protagonist to be a gay man persecuted by the local community.

It was to be about a sensitive young teacher, a follower of A.S. Neill faced with a problem child in an unsympathetic mining town, a man who has hardly admitted to himself that he is homosexual. He is falsely accused of a sexual offence against the boy and goes to gaol. Later I changed the outcome: he is cleared of the charge but in the course of his defence he has revealed enough about himself to make his return to the community more difficult than before. It was to be a very subjective novel full of anxiety and guilt.

The essay gives a broad outline of his development as a novelist, and covers many of the literary influences of the young Pearson, providing evidence that, had he found the wherewithal to get beyond his fear of being exposed as gay, he would have accomplished much more of importance to New Zealand fiction writing.

However, although not publishing another novel after Coal Flat, Pearson did go onto to publish other important work, including a detailed study of the Australian writer and poet, Henry Lawson, during his time spent living in New Zealand: Henry Lawson Among Maoris.
Another work — more entertaining albeit much shorter — that Pearson was responsible for was a short ditty about James K Baxter, which originally appeared in the Canterbury Student's magazine, Canta, while Pearson was editor and Baxter was the literary editor:

Mrs Baxter’s little Jim
Got immersed in sex and sin.
When the pangs of doubt grow violent
Beer’s the universal solvent.
But in between the rum and vomit
A poem flashes like a comet.

For the last issue of the year Christine organised a page of mutual self-congratulation with cartoons of Baxter, herself and me accompanied by some teasing verse. Ray Copeland, then a fellow M.A. student of English chose to adapt some of Chaucer’s lines (on his Clerk) to go beneath the sketch of me, and I wrote the lines about Baxter. I recall the bad rhyme of the second couplet worried me at the time.

Pearson was a conscientious and sensitive individual, and was very concerned about — and involved in — the peace movement of the latter half of the 20th century. During the Second World War, he agonised about joining the army, eventually deciding to do so only in a non-combatant role (as a dental orderly), although he later accepted a posting to an infantry unit which give him much pause for thought:

In the army I re-thought my position and concluded I could no longer logically object to combatant service. So I made no objection when I was unexpectedly transferred to the infantry, and was a member of the last reinforcement to go to Egypt and Italy, and of the first party to go to Japan as part of the occupation force. At Ma'adi I saw a sergeant practicing with a flame-thrower and I asked myself, Would I be capable of using a weapon like that? For a cause that I believed in? But having thrown away the principle I couldn't come up with any answer that made me easy.

After Coal Flat, Pearson acted as editor of Frank Sargeson's Collected Stories (1964) and a selection of Pearson's essays and reviews on literature and society were collected in Fretful Sleepers and Other Essays (1974).

Returning from London to teach in the English Department at Auckland University in 1954, Pearson found himself becoming associated with the small community of Maori students (35 from a roll of over 3000), and assisting them both academically and financially. Interestingly, Dr Pita Sharples was one who benefited greatly from Pearson's input.